This invention is generally concerned with sheet feeding and cutting apparatus and more particularly with methods and apparatus for cutting sheets from a continuously moving web thereof.
In U.S. Pat. No. 4,593,893 for A Method And Apparatus For Sequentially Advancing and Cutting Forms From Two Continuous Form-Webs, issued Jun. 10, 1986 to Walter Suter, there is described structure for feeding a web of sheets in a downstream path of travel between opposed knife cutters, extending transverse to the path of travel, for cutting respective sheets from the web. Due to such cutters typically having a cutting cycle of from 80 to 100 milliseconds, if a typical web feeding speed of 100 inches per second is assumed, then, 8 to 10 inches of the length of the web would be jammed against the cutters during each cutting cycle if web feeding was not stopped during the cutting cycle. As a result, the throughput rate of feeding the web to and through the cutting structure is reduced by the lapsed time interval needed to temporarily stop the web for cutting each sheet therefrom.
In U.S. Pat. No. 4,014,535 for a Continuous Sheet Collating Method and Apparatus, issued Mar. 19, 1977 to Robert E. Kleid et al., there is described structure for continuously feeding a web of sheets in a downstream path of travel between opposed rotary sheet feeding drums, one of which is a collating drum and the other of which is equipped with a cutter that extends transverse to the path of travel. Although this patent is primarily concerned with the disclosure of collation structure, it also discloses typical rotary web cutting structure including a rotary cutting drum having a circumference which is equal to the length of the sheets cut from the web. And illustrates the fact that the physical dimensions of the cutting drum must be made proportional to the length of sheets which are to be cut from a given web, since different lengths of sheets, which are not equal to or a multiple of the circumferential length of the cutting drum, could not be cut from the web without stopping operation of the equipment and changing the cutting drum.
In U.S. Pat. No. 2,114,415, for an Art Of Manufacturing Folded Paper Articles, issued Apr. 19, 1938 to Samuel J. Campbell, there is described structure for continuously feeding a fan-folded web in a downstream path of travel and into engagement with a transversely extending band-blade cutter, which has a cutting belt run which extends parallel to and is located midway between the opposed fold edges of the web for cutting two folded sheets at a time from the web. Although this Patent exemplifies usage of a band blade cutter for cutting sheets from a continuous web like the rotary cutting structure of the above discussed Kleid et al. patent the physical dimensions of the equipment, in this instance the fan folding structure, would have to be changed to cut sheets of different or varying dimensions from a web.
Accordingly:
An object of the invention is to provide improved web feeding and cutting apparatus;
Another object is to provide improved methods and apparatus for cutting sheets of different or varying lengths from a web thereof; and
Another object is to provide high speed web feeding and cutting apparatus, including structure for cutting respective sheets from the web as the web is continuously moving.